Project Summary/Abstract Lack of effective strategies to achieve cytotoxic concentrations of anticancer drugs in deep-seated and metastatic cancers has been a major barrier to improving treatment outcomes in lung cancer. Mesenchymal stem cells (MSCs) possess exquisite tumor homing capabilities, and thus have the potential to selectively deliver anticancer therapies to tumor tissues. A number of previous studies have shown that genetically modified MSCs can be used to deliver anticancer peptides and proteins to tumor tissues. However, MSCs have not been explored so far to deliver small molecules likely because of the difficulty in immobilizing small molecules in cells for sustained duration. The overall objective of this study is to investigate the efficacy of nano-engineered MSCs (Nano-MSC) in lung cancer. We hypothesize that MSCs engineered to carry drug-loaded, polymeric nanoparticles will allow for tumor-targeted and sustained delivery of cytotoxic drugs, resulting in effective inhibition of lung tumor growth. The specific aims of the proposed research are to 1) Nano-engineer MSCs for cytotoxic drug delivery and 2) Determine the anticancer efficacy of nano-engineered MSCs in a mouse orthotopic model of lung cancer. Studies in Specific Aim 1 will focus on optimizing the cell engineering strategies to achieve high cytotoxic payload in MSCs without affecting their viability or tumor homing properties. Paclitaxel will be used as a model cytotoxic drug. We will compare the efficiency of simple endocytic uptake against (1) TAT peptide mediated cytosolic delivery and (2) covalent conjugation of nanoparticles to MSC surface for nano-engineering MSCs. In vitro studies examining the effect of nanoparticles on cell uptake, cytotoxicity and differentiation potential against human MSCs as well as inhibition of proliferation of cancer cells when co-incubated with nano-engineered MSCs will be used to optimize the delivery parameters. Studies in Specific Aim 2 will (i) determine the kinetics of paclitaxel delivery to lung tumors using MSCs and (ii) optimize the dose for achieving effective tumor growth inhibition in a mouse orthotopic model of lung cancer. Relevance: High mortality rate associated with lung cancer warrants the development of novel approaches that are effective against advanced disease. The studies proposed in this application will advance a novel therapeutic strategy combining active targeting using MSCs and sustained drug delivery using a safe, non-toxic vector. The successful completion of the proposed studies will provide critical data establishing the feasibility of this approach. Such data is critical for the further preclinical development of this unique, cell-based targeting strategy.